The present invention relates to a battery pack to be used in a mobile radio apparatus such as a mobile telephone, a personal handy phone system (PHS) etc., and more particularly to a battery pack into which water is easy to enter, so that a quick response to a water leakage can be obtained.
Conventionally, with respect to a mobile radio apparatus such as a mobile telephone, PHS etc., there are many cases wherein a water leakage detecting seal is attached between a battery cell and a case, or between upper and lower cases. FIGS. 5 through 7 show one example of such a battery pack as constructed in this way to have the conventional water leakage detecting seal attached to the case.
FIG. 5 is a perspective view showing a structure of the conventional battery case with a water leakage detecting seal. As shown in FIG. 5, the water leakage detecting seal 12 is attached to the case of the battery pack 11. FIG. 6 is a side view in cross section taken along a line A--A in FIG. 5. In FIG. 6, the battery pack 11 is so constructed that a battery cell 17 and a protective circuit 14 for protecting the battery are provided between a case A 15 and a case B 16.
FIG. 7 is an enlarged side view in cross section of a part of FIG. 6. In FIG. 7, the water leakage detecting seal 12 is directly attached to the case B 16 between the battery cell 17 and the case B 16 just below a window 13.
In the conventional structure as shown in FIG. 7, a gap between the water leakage detecting seal and the case B must be as small as possible in order to prevent the seal from being peeled off by a pressure from the outside through the window 13. For this reason, water is hard to enter into the gap so as to reach the water leakage detecting seal 12, and a problem lies in that the detecting seal is too slow to respond to the water leakage.